I just installed the Arduino IDE 2.0 beta and plugged my Arduino Uno in, but the IDE could not find the COM3 port with the Uno. Then I installed the Arduino IDE 1.8.16, which was able to recognize the Uno on COM3, and uploaded the Blink example. After all this, I reopened the 2.0 IDE and it was now able to recognize the Uno on COM3 and upload code to it.
I'm guessing the optional USB drivers were missing in the 2.0 IDE installer?
There were optional modules I installed with the 1.8.16 IDE (see screenshot below) that the 2.0 IDE installer did not prompt me for.